Why do global climate models behave like they do? The Coupled Model Intercomparison Project (CMIP) panel—a subcommittee of the World Climate Research Programme—designs experiments to evaluate differences among climate models in how they simulate our global climate system and predict future changes.

From record-low Arctic sea ice to the highest global sea level of the modern record, the 2012 State of the Climate report provides a complete rundown on the state of Earth's climate and how it is changing.

The extent of snow-covered ground in the Northern Hemisphere at the end of the cold season (June) hit a record low. Annual average snow cover extent has not exceeded the long-term average even once since 2003. Between 1979 and 2011, the snow cover in June is declining even faster than the end-of-summer Arctic sea ice extent.

Glacier mass balance in 2011 (the most recent year for which worldwide analysis is complete) was negative, and preliminary data indicate that 2012 will probably be the 22nd consecutive year of net losses in glacier mass. Between 1980 and 2011, glaciers around the world lost the water equivalent of 15.7 meters. That would be like slicing a roughly 17-meter-thick slab off the top of the average glacier and repeating that exercise worldwide.

They say the grass is always greener on the other side of the fence, and that was certainly true in June. Throughout the month, two very different stories played out in the contiguous United States. While the drought-stricken West fell into the grips of an intense heat wave, East Coasters were bombarded by summer thunderstorms.

Tampa Bay Water Supply Manager Allison Adams knows water is precious for the millions of residents who rely on the water agency for drinking water and recreation, and for the region’s natural ecosystems, including wetlands and lakes. Adams and colleagues discuss how their evolving water management approach allows them to balance diverse water needs in the face of often unpredictable water sources and cycles.

Tampa Bay Water provides safe, potable drinking water to 2.3 million people in the Tampa Bay region. But future availability of surface water can be hard to predict, and drought is a recurring challenge there. The water utility managers are increasingly using seasonal climate forecasts to track climate variability, which helps them better plan their water supply and reduce their vulnerability to seasonal climate impacts.

The Spring Outlook encompasses temperature, precipitation, drought, and flooding expectations for the coming three months, and Mike Halpert, Acting Director of the Climate Prediction Center, discusses the outlook and its implications.